The invention is based on an electromagnetic valve of the general type having an armature isolated from the flow of pressure medium and a valve actuated by the armature via an actuating push rod, said valve being disposed with its valve closing body in a passageway which experiences the flow through it of a pressure medium. A valve of this type is known (German Offenlegungsschrift No. 30 06 576).
The known electromagnetic valve is a two-way valve having a seated valve which upon excitation of the magnet is forced open by the armature via a push rod. It has the disadvantage that is is capable of assuming only two positions and that in order to attain a three-positional function, two such two-position valves are necessary.
A further disadvantage is that such a valve can be used only for compressed air and that in its outset position it is not tightly sealed. Finally, its sole purpose is flow control; it does not have a seated valve capable of completely shutting off the flow.
A magnetically actuated three-position valve does already exist (German Auslegeschrift No. 22 57 213); however, in this known valve there is a flow of pressure medium through the armature. This is disadvantageous if the valve must be designed for high pressures, because the sheath receiving the armature must then be especially embodied so that it is absolutely pressure-tight. This is complicated and expensive.